74181 is 4-bit arithmetic and logic unit introduced by Texas Instruments in March 1970 and it is known for being the first ALU in single package. This chip is no longer in manufacturing but still it is quite popular in CA (computer architecture) courses in many colleges.

To test the behavior of this 4-bit ALU we decided to construct it on Altera MAX II CPLD. For this project we choose EPM240T100C5 CPLD and logic design is implement using Altera Quartus II. For logic design we refer Fairchild Semiconductor’s DM74LS181 datasheet. This setup is tested on basic EPM240 series development board with some mechanical switches and couple of LEDs.

74181 4-bit ALU test setup with EPM240T100C5 development board.
74181 4-bit ALU test setup with EPM240T100C5 development board.

There are several test circuits available for 74181 ALU and our test setup is partially based on Electronics for Your (EFY) 1997 article. In another test setup we use HEF4040 to driver, A and B operands of this ALU.

The test setup attached into this article is the minimum configuration which anyone can build with small number of components.

Project Related Downloads

Altera Quartus project file and test setup for 74181 ALU design.


DM74LS181 - 4-Bit Arithmetic Logic Unit
EPM240T100C5 - Altera MAX II - 192 Macro, 80 I/O CPLD
HEF4040 - 12-Stage Binary Ripple Counter
EFY (2005), Electronics Projects Vol. 18 - page 118-121